#!/bin/bash
#
# Developed by Fred Weinhaus 12/8/2012 .......... revised 4/25/2015
#
# ------------------------------------------------------------------------------
# 
# Licensing:
# 
# Copyright © Fred Weinhaus
# 
# My scripts are available free of charge for non-commercial use, ONLY.
# 
# For use of my scripts in commercial (for-profit) environments or 
# non-free applications, please contact me (Fred Weinhaus) for 
# licensing arrangements. My email address is fmw at alink dot net.
# 
# If you: 1) redistribute, 2) incorporate any of these scripts into other 
# free applications or 3) reprogram them in another scripting language, 
# then you must contact me for permission, especially if the result might 
# be used in a commercial or for-profit environment.
# 
# My scripts are also subject, in a subordinate manner, to the ImageMagick 
# license, which can be found at: http://www.imagemagick.org/script/license.php
# 
# ------------------------------------------------------------------------------
# 
####
#
# USAGE: softlight [-a amount] [-s smooth] [-p percent] [-c color] infile outfile
# USAGE: softlight [-h or -help]
# 
# OPTIONS:
# 
# -a     amount       amount (intensity) of soft light; 0<=integer<=100; 
#                     default=80
# -s     smooth       smoothing extent of soft light; integer>=0; default=50
# -p     percent      percent of white from thresholding; 0<=integer<=100; 
#                     default=5
# -c     color        color of softlight; any valid opaque IM color; 
#                     default=white
# 
###
# 
# NAME: SOFTLIGHT 
# 
# PURPOSE: To apply soft light to an image.
# 
# DESCRIPTION: SOFTLIGHT applies soft light to an image.
# 
# 
# ARGUMENTS: 
# 
# -a amount ... AMOUNT (intensity) of soft light. Values are integers between 
# 0 and 100. The default=80.
# 
# -s smooth ... SMOOTH is the smoothing extent of the soft light. Values are 
# integers greater or equal to 0.  The default=50.
# 
# -p percent ...PERCENT of white from thresholding used to create the soft 
# light. Values are integers between 0 and 100. The default=5.
# 
# -c color ... COLOR of the soft light. Any valid opaque IM color is allowed. 
# The default=white.
# 
# CAVEAT: No guarantee that this script will work on all platforms, 
# nor that trapping of inconsistent parameters is complete and 
# foolproof. Use At Your Own Risk. 
# 
######
# 

# set default values
amount=80			# amount (intensity, attenuation)
smooth=50			# smoothing extent
percent=5			# percent white threshold
color="white"		# light color

# set directory for temporary files
dir="."    # suggestions are dir="." or dir="/tmp"

# set up functions to report Usage and Usage with Description
PROGNAME=`type $0 | awk '{print $3}'`  # search for executable on path
PROGDIR=`dirname $PROGNAME`            # extract directory of program
PROGNAME=`basename $PROGNAME`          # base name of program
usage1() 
	{
	echo >&2 ""
	echo >&2 "$PROGNAME:" "$@"
	sed >&2 -e '1,/^####/d;  /^###/g;  /^#/!q;  s/^#//;  s/^ //;  4,$p' "$PROGDIR/$PROGNAME"
	}
usage2() 
	{
	echo >&2 ""
	echo >&2 "$PROGNAME:" "$@"
	sed >&2 -e '1,/^####/d;  /^######/g;  /^#/!q;  s/^#*//;  s/^ //;  4,$p' "$PROGDIR/$PROGNAME"
	}

getMinMax()
	{
	img="$1"
	# statistics computed as percent (of dynamic range) values
	if [ "$im_version" -ge "06030901" ]
		then 
		min=`convert $img -format "%[min]" info:`
		max=`convert $img -format "%[max]" info:`
		min=`convert xc: -format "%[fx:100*$min/quantumrange]" info:`
		max=`convert xc: -format "%[fx:100*$max/quantumrange]" info:`
	else
		data=`convert $img -verbose info:`
		min=`echo "$data" | sed -n 's/^.*[Mm]in:.*[(]\([0-9.]*\).*$/\1/p ' | head -1`
		max=`echo "$data" | sed -n 's/^.*[Mm]ax:.*[(]\([0-9.]*\).*$/\1/p ' | head -1`
		min=`convert xc: -format "%[fx:100*$min]" info:`
		max=`convert xc: -format "%[fx:100*$max]" info:`
	fi
	}

# function to report error messages
errMsg()
	{
	echo ""
	echo $1
	echo ""
	usage1
	exit 1
	}


# function to test for minus at start of value of second part of option 1 or 2
checkMinus()
	{
	test=`echo "$1" | grep -c '^-.*$'`   # returns 1 if match; 0 otherwise
    [ $test -eq 1 ] && errMsg "$errorMsg"
	}

# test for correct number of arguments and get values
if [ $# -eq 0 ]
	then
	# help information
   echo ""
   usage2
   exit 0
elif [ $# -gt 10 ]
	then
	errMsg "--- TOO MANY ARGUMENTS WERE PROVIDED ---"
else
	while [ $# -gt 0 ]
		do
			# get parameter values
			case "$1" in
		  -h|-help)    # help information
					   echo ""
					   usage2
					   exit 0
					   ;;
				-a)    # get amount
					   shift  # to get the next parameter
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID AMOUNT SPECIFICATION ---"
					   checkMinus "$1"
					   amount=`expr "$1" : '\([0-9]*\)'`
					   [ "$amount" = "" ] && errMsg "--- AMOUNT=$amount MUST BE A NON-NEGATIVE INTEGER VALUE (with no sign) ---"
					   test1=`echo "$amount < 0" | bc`
					   test2=`echo "$amount > 100" | bc`
					   [ $test1 -eq 1 -o $test2 -eq 1 ] && errMsg "--- AMOUNT=$amount MUST BE AN INTEGER BETWEEN 0 AND 100 ---"
					   ;;
				-s)    # get smooth
					   shift  # to get the next parameter
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID SMOOTH SPECIFICATION ---"
					   checkMinus "$1"
					   smooth=`expr "$1" : '\([0-9]*\)'`
					   [ "$smooth" = "" ] && errMsg "--- SMOOTH=$smooth MUST BE A NON-NEGATIVE INTEGER ---"
					   ;;
				-p)    # get percent
					   shift  # to get the next parameter
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID PERCENT SPECIFICATION ---"
					   checkMinus "$1"
					   percent=`expr "$1" : '\([0-9]*\)'`
					   [ "$percent" = "" ] && errMsg "--- PERCENT=$percent MUST BE A NON-NEGATIVE INTEGER VALUE (with no sign) ---"
					   test1=`echo "$percent < 0" | bc`
					   test2=`echo "$percent > 100" | bc`
					   [ $test1 -eq 1 -o $test2 -eq 1 ] && errMsg "--- PERCENT=$percent MUST BE AN INTEGER BETWEEN 0 AND 100 ---"
					   ;;
				-c)    # get color
					   shift  # to get the next parameter
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID COLOR SPECIFICATION ---"
					   checkMinus "$1"
					   color="$1"
					   ;;
				 -)    # STDIN and end of arguments
					   break
					   ;;
				-*)    # any other - argument
					   errMsg "--- UNKNOWN OPTION ---"
					   ;;
		     	 *)    # end of arguments
					   break
					   ;;
			esac
			shift   # next option
	done
	#
	# get infile and outfile
	infile="$1"
	outfile="$2"
fi

# test that infile provided
[ "$infile" = "" ] && errMsg "--- NO INPUT FILE SPECIFIED ---"

# test that outfile provided
[ "$outfile" = "" ] && errMsg "--- NO OUTPUT FILE SPECIFIED ---"

# set up temp files
tmpA1="$dir/softlight_A_$$.mpc"
tmpA2="$dir/softlight_A_$$.cache"
trap "rm -f $tmpA1 $tmpA2;" 0
trap "rm -f $tmpA1 $tmpA2; exit 1" 1 2 3 15
trap "rm -f $tmpA1 $tmpA2; exit 1" ERR


# get im version
im_version=`convert -list configure | \
	sed '/^LIB_VERSION_NUMBER */!d; s//,/;  s/,/,0/g;  s/,0*\([0-9][0-9]\)/\1/g' | head -n 1`

# colorspace RGB and sRGB swapped between 6.7.5.5 and 6.7.6.7 
# though probably not resolved until the latter
# then -colorspace gray changed to linear between 6.7.6.7 and 6.7.8.2 
# then -separate converted to linear gray channels between 6.7.6.7 and 6.7.8.2,
# though probably not resolved until the latter
# so -colorspace HSL/HSB -separate and -colorspace gray became linear
# but we need to use -set colorspace RGB before using them at appropriate times
# so that results stay as in original script
# The following was determined from various version tests using softlight.
# with IM 6.7.4.10, 6.7.6.10, 6.8.0.8
if [ "$im_version" -lt "06070607" -o "$im_version" -gt "06070707" ]; then
	setcspace="-set colorspace RGB"
else
	setcspace=""
fi
# no need for setcspace for grayscale or channels after 6.8.5.4
if [ "$im_version" -gt "06080504" ]; then
	setcspace=""
fi


# read input image
convert -quiet "$infile" $setcspace +repage $tmpA1 ||
	errMsg  "--- FILE $infile DOES NOT EXIST OR IS NOT AN ORDINARY FILE, NOT READABLE OR HAS ZERO SIZE  ---"


# change amount from percent to fraction
amount=`convert xc: -format "%[fx:$amount/100]" info:`

# set up auto level
if [ "$im_version" -lt "06050501" ]; then
	getMinMax $tmpA1
	autoleveling="-level $min%,$max%"
else
	autoleveling="-auto-level"
fi


# get mask of top percent closest to white
# approximated using negated saturation and brightness channels multiplied
# blur mask and multiply by attenuation factor
# apply as mask to overlay white
convert $tmpA1 \
	\( -clone 0 -fill $color -colorize 100% \) \
	\( -clone 0 -colorspace HSB -channel G -negate -channel GB -separate +channel \
		-compose multiply -composite -contrast-stretch 0,${percent}% \
		-fill black +opaque white -blur 0x$smooth \
		$autoleveling -evaluate multiply $amount \) \
	-compose over -composite "$outfile"


exit 0










